Kalvimalar

Psychological scientist Angelina R Sutin at the National Institute on Aging (NIA) at the National Institutes of Health (NIH) in US, predicted that people in the same "birth cohort" - born around the same time - may have had unique experiences that shape the way they evaluate happiness and optimism.

They hypothesised that the level of well-being a person reports would, therefore, vary according to his or her birth year.

Using two large-scale longitudinal studies, NIH's Baltimore Longitudinal Study of Aging (BLSA) and the CDC's National Health and Nutrition Examination Survey (NHANES), Sutin and colleagues looked at data from several thousand people over 30 years, including over 10,000 reports on well-being, health, and other factors.

When the researchers analysed the data across the whole pool of participants, older adults had lower levels of well-being than younger and middle-aged adults.

But when they analysed the same data while taking birth cohort into account, a different trend appeared: Life satisfaction increased over the participants' lifetimes. This

trend remained even after factors like health, medication, sex, ethnicity, and education were taken into account.

While life satisfaction increased with age for each cohort, older birth cohorts - especially people born between 1885 and 1925 - started off with lower levels of well-being in comparison to people born more recently.

Looking at life satisfaction across all of the participants, regardless of when they were born, obscures the fact that each cohort actually shows the same underlying trend.

Researchers pointed out that the level of well-being of cohorts born in the early part of the 20th century, particularly those who lived through the Great Depression, was substantially lower than the level of well-being of cohorts who grew up during more prosperous times.

The greater well-being of more recent cohorts could be the result of economic prosperity, increased educational opportunities, and the expansion of social and public programmes in the US over the latter half of the 20th century.

The study was published in Psychological Science, a journal of the Association for Psychological Science.